Dynamoelectric machine



June 14, 1949. RJA. FULLER 2,473,244

DYNAMOELECTRIC MACHINE Filed Dec. 28, 1945 Inventor:

H i s AttOTh e yv Patented June 14, 1949 DYNAMOELECTRIC MACHINE Roger A. Fuller, Fort Wayne, Ind., assignor to General Electric Company, a corporation of New York Application December 28, 1945, Serial No. 637,673

6 Claims. (Cl. 318-207) My invention relates to dynamoelectric r'nachines and particularly to'reyersible induction motors having starting windings which are adapted to be energized in opposite directions of the motor in a clockwise direction as indicated by the letters CW in the drawing and for alternately closing the circuit of the motor on the source of electrical power supply for rotation in the opposite direction; that is in a counterclockwise direction, as indicated by the letters "CCW on the drawing. Since an induction motor of this type is adapted to continue rotating in either direction when the rotatable membar I has been started and is operating above a 2 predetermined speed when the running field exciting winding 2 is energized in the same sense on closure of the reversing switch I in either direction. As shown, the terminal of the running for obtaining rotation of the machine in opposite 5 field exciting winding 2 on one side thereof, condirections. nected to contacts 9 and I0, and the terminal of An object of my invention is to provide an the other side of the winding 2, connected to the improved reversible type dynamoelectric machine. contacts H and I2, are adapted to be closed across Another object of my invention is to provide the source of energization 8 by contactors l3 and an improved dynam-oelectric machine of the in- 10 [4, respectively, for energization in the same duction motor type adapted to operate in both direction. In order to reverse the direction of directions of rotation. rotation of the rotatable member I, it, therefore,

Further objects and advantages of my invenis necessary that the starting field exciting windtion will become apparent and my invention will ing 3 be energized in opposite directions, and be better understood from the following descripthis is obtained by rendering ineffective the eftion referring tothe accompanying drawing, and fects of the speed responsive circuit breaker the features of novelty which characterize my 5--6'l by connecting the terminals of this field invention will be pointed out with particularity exciting winding 3 for reversev energization by in the claims annexed to and forming part of reversing switch coptactors l5 and I6. As shown. this specification. one terminal of the field exciting winding 3 is The drawing is a schematic diagram oi a caconnected to contacts l1 and I8, and the other pacitor type motor illustrating one embodiment terminal of the field exciting winding 3 is conof my invention. nected to terminals l9 and 20, such that the Referring to the drawing, I have shown a caenergization of the field exciting winding 3 by pacitor type induction motor provided with an the source of electrical power supply 8 is in one embodiment of my invention and having a rotatdirection when the reversing switch 1 is closed able member I provided with a conventional type for a clockwise direction of rotation by connecwinding which may be of the squirrel cage type tion of the source of power 8 to the terminals and a stationary member having a running field l1 and 20 and by'connection of the terminals of exciting winding 2 and a starting field exciting 30 the field exciting winding 3 to the switch conwinding 3 which is arranged with correspondtacts l8 and I9 when the reversing switch I is ing parts thereof displaced from the running closed in a counterclockwise direction. This, field exciting winding 2. In this system, the however, would not be sufiicient to obtain a starting field exciting winding 3 is connected reversal of direction of rotation of the rotatable in series with a capacitor 4 and contacts 5 and 3 member under most conditions, as when the 6 of a centrifugal switch which forms part of rotatable member I is operating aboveapredetera circuit breaker operable in response to the speed mined speed, the circuit of the starting field excitof the rotatable member I by any suitable centriing winding is opened by the centrifugal switch trifugal mechanism 1 for opening the circuit of through the contacts 5 and 6, and reversal of the the starting winding 3 above a predetermined 40 reversing switch I would not energize the startspeed and for reclosing this open circuit below ing field exciting winding 3 as long as the cenapredetermined rotatable member-speed. In this trifugal switch contacts 5 and Ii remain open, arrangement, I provide a reversing switch I which and, therefore, the speed of the rotatable member is adapted to close the circuit of the motor on I would not decrease, and thesecontacts 5 and asource of electrical power supply 8 for rotation 3 would not close and the starting winding 3 would remain deenergized. In order to assure reversal of the motor substantially instantaneously, or at least within a very short period of time, the reversing switch I is provided with a time delay circuit breaker arrangement which includes contacts 2| connected across the speed responsive circuit breaker contacts 5 and 6. This time delay circuit breaker is adapted to close the circuit across the speed responsive circuit breaker contacts 5 and G on operation of the reversing switch I from one closed circuit position to the other by the operation of a suitable device. such as a cam 22, adapted to operate a contactor 23 of the time delay circuit breaker to closed .circuit position across the contacts 2! as the switch 1 passes through its open circuit position. The time delay circuit breaker is provided with any suitable time delay device 24 which may be adjusted to remain in its closed circuit position for any desired predetermined time after it is released by the cam 22. Such a time delay mechanism 2| may be of the ticker interlock type or a dashpot mechanical time delay or any other suitable similar arrangement which is adapted to open the circuit through the contactor 23 by operation of the contactor, as indicated by the arrow 25 after a predetermined elapse of time after closure of this circuit breaker. Thus, when the reversing switch I is closed from one position to another closed circuit position, the starting field excitin winding 3 is energized in the opposite direction from that required for running the motor in the direction in which it originally operated, and this provides a braking torque in the motor which assists in bringing the rotatable member I to a quick stop and then exerts a starting torque for rotation of the rotatable member I in the opposite direction. This operation of the motor is equally applicable for reversal in direction of rotation from clockwise rotation to counterclockwise rotation and for the reversal from counterclockwise rotation to clockwise rotation.

While I have illustrated and described a particular embodiment of my invention, modifications thereof will occur to those skilled in the art. I desire it to be understood, therefore, that my invention is not to be limited to the particular arrangement disclosed, and I intend in the appended claims to cover all modifications which do not depart from the spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. An induction motor having a rotatable member with a rotor winding, a running field exciting winding and a starting field exciting winding, means including a circuit, breaker responsive to the speed of said rotatable member for opening and closing the circuit of said starting field exciting winding dependent on the rotatable mem ber speed, means for energizing said running field exciting winding, means for connecting said starting field exciting windin for energization in pposite directions, a mechanical time delay means mechanically connected to said last named means and operable thereby for rendering ineffective the effects of said speed responsive circuit breaker for a predetermined time on connection of said starting field exciting winding for energization in either direction whereby said rotatable member may be stopped and restarted in either direction.

2. An induction motor having a rotatable mem ber with a rotor Winding, a running field exciting winding and a starting field exciting winding, means including a circuit breaker responsive to the speed of said rotatable member for opening and closing the circuit of said starting field exciting windin dependent on the rotatable member speed, means for energizing said running field exciting winding, means for connecting said starting field exciting winding for energization in opposite directions, and a mechanical time delay means mechanically connectedto said last named means and operable thereby for closing the circuit of said starting field exciting winding across said speed responsive circuit breaker for a predetermined time on connection or said starting field exciting winding for energization in either direction whereby said rotatable member may be stopped and restarted in either direcion.

3. An induction motor having a rotatable member with a winding, a stationary member with a running field exciting winding and a starting field exciting winding having corresponding parts thereof displaced from said running field exciting winding, a capacitance connected in series with said starting field exciting winding, means including a circuit breaker responsive to the speed of said rotatable member for opening and closing the circuit of said starting field exciting winding above and below a predetermined speed respectively, means for energizing said running field exciting winding, means for connecting said starting field exciting winding for energization in opposite directions, and a mechanical time delay means mechanically connected to said last named means and operable thereby for closing the circuit of said starting field exciting winding across said speed responsive circuit breaker for a predetermined time on connection of said starting field exciting winding for energization in either direction whereby said rotatable member may be stopped and restarted in either direction.

4. An induction motor having a rotatable member with a winding, a stationary member with a running field exciting winding and a starting field exciting winding, a capacitance connected in circuit with said starting fieldexciting winding, means including a circuit breaker responsive to the speed of said rotatable member for opening the circuit of said starting field exciting winding above a predetermined speed and for reclosing said open circuit below a predetermined rotatable member speed, means including a reversing switch for energizing said running field exciting winding in the same sense on a closure thereof in both directions, means including said reversing switch for connecting said starting field exciting winding for energization in opposite directions, and a circuit breaker of the mechanical time delay type mechanically connected to said reversing switch and operable thereby for closing the circuit of said starting field exciting winding across said speed responsive circuit breaker for a predetermined time on operation of said reversing switch from one closed circuit position to the other whereby said rotatable member may be stopped and restarted in either direction.

5. An induction motor having a rotatable member with a rotor winding, a running field exciting winding and a starting field exciting winding, means including a circuit breaker responsive to the speed of said rotatable member for opening and closing the circuit of said starting field exciting winding dependent on the rotatable member speed, means including a reversing switch for energizing said running field exciting winding in the same sense oh a. closure thereof in both directions, means including said reversing switch for connecting said starting field exciting winding for energization in opposite directions on closure thereof in opposite directions, and a mechanical time delay means mechanically connected to said reversing switch and operable thereby for closing the circuit of said starting field exciting winding across said speed responsive circuit breaker for an adjustable predetermined time on operation of said reversing switch from one closed circuit position to the other whereby a braking torque is generated on said motor rotating in one direction when said reversingswitch is closed for rotation in the opposite direction so that said rotatable member may be stopped and restarted in either direction.

6. An induction motor having a rotatable member with a winding, a stationary member with a running field exciting winding and a starting field exciting winding having corresponding parts thereof displaced from said running field exciting winding, a capacitance connected in circuit with said starting field exciting winding, means including a circuit breaker responsive to the speed of said rotatable member for opening the circuit of' said starting field exciting winding above a predetermined speed and for reclosing said open circuit below a predetermined rotatable member for connecting said starting field exciting wind-' ing for energizatlon in opposite directions on closure thereof in opposite directions, and means including another circuit breaker mechanically connected to said reversing switch and operable thereby, said circuit breaker being arranged across said speed responsive circuit breaker for closing the circuit of said starting field exciting winding across said speed responsive circuit breaker on operation of said reversing switch from one closed circuit position to the other, and a mechanical time delay device for holding closed said other circuit breaker for a predetermined time after closure thereof responsive to closure of said reversing switch in either direction where by a braking torque is generated on said motor rotating in one direction when said reversing switch is closed for rotation in the opposite direction so that said rotatable member may be stopped and restarted in either direction.

ROGER A. FULLER.

REFERENCES CITED The following references are of record in the file of this patent:

' UNITED STATES PATENTS Number Name Date 2,117,123 Werner May 10, 1938 2,280,888 Buchanan Apr. 28, 1942 

